It's a ten year deal. WOW! 20 Cup races, seven on NBC and 13 on NBC Sports Network. 19 Nationwide races (four on NBC, 15 on NBC Sports Network), NASCAR K&N Series, NASCAR Whelen Modified Series all part of the deal. NBC also obtains exclusive rights to the Hall of Fame and to the Awards Ceremonies. Huge huge deal.
Three Cup races and 14 Nationwide races still "up for grabs" but Brian France indicated those would go to FOX Sports along with the 13 Cup races already on FOX and the Truck Series. FOX has exclusive rights to the Daytona 500. FOX's deal runs through 2022, NBC's through 2024. Despite Daytona being on FOX, NBC is the main television partner.
FOX and NBC already have rights to the ARCA Racing Series. NBC will begin televising the ARCA Series in August.
NBC also airs the majority of the IZOD IndyCar Series races and all of the Formula One races.
In short: Good riddance TNT
and NBC Sports Network = NBC Motorsports Channel